I forgot my Apple ID and I can't access my iPad

If you were the original purchaser and can prove it with

a receipt from Apple or Apple authorized iPad retailer showing

the serial number of the iPad, make a genius bar

reservation and bring in the receipt, iPad, and government

issued photo ID to Apple and they may assist in resolving the problem.

If the iPad was purchased used or there is no receipt, the AppleID and passcode must be recovered 

It is highly recommended that you make a Genius Bar Reservation to avoid delay at the Apple store

https://www.apple.com/retail/geniusbar/

Otherwise, you will need to recover the AppleID and passcode used to

initiate the Activation Lock.

Apple cannot access any data on the locked device - as all data is encrypted. The encryption key is stored within the iPad security chip (the “secure enclave”); your iPad Passcode unlocks the secure enclave which, in turn, releases the encryption key to the Operating System. The encryption key decrypts the data.

If the iPad Passcode has been lost or forgotten, the encryption key intentionally remains beyond reach; if the iPad is disabled, the encryption key is destroyed - rendering the data permanently inaccessible.

The Activation Lock prevents the [possibly stolen] iPad from being reset or reused - unless the AppleiD credentials that last activated the iPad can be provided. This ensures that only the bona-fide owner can reactivate and reuse an iPad that has been reset from a disabled state. Apple require the original sales invoice, that includes an imprint of the device serial number as acceptable proof of ownership. When provided, Apple will provide help.

Sounds like the iPad is activation locked. Learn how Activation Lock can be removed: https://support.apple.com/en-us/HT201441

Then you have no other options. Recycle the iPad as it will be of no use to you.

Yes. You'll never get access unless you can prove ownership; which you inferred you cannot.

Welcome, PeterMAC19, to Apple Support Communities!

The Activation Lock is an anti-theft feature.

That’s why Apple requires some semblance of proof of ownership in order to assist in unlocking.

(Early on, iPhone users were killed for their iPhones. That’s when Apple decided to make it, essentially, impossible for people to steal iPhones [without the resulting iPhone being useless to the thief].)

A number of years ago (five or so), my wife’s iPad Pro (10 inch, or so) was stolen.

Fortunately, it was Activation Locked, so no one could access her data.

Unfortunately, we never recovered her iPad. (A couple of thousand dollars lost.)

As described, without acceptable proof of ownership, your locked/disabled iPad is indistinguishable from a stolen device. As such, Apple will not assist with removing the security measures that are intended to render a stolen device worthless to anyone other than the bona-fide owner.

Unfortunately, whilst you may in fact be the genuine owner, you are unable to provide acceptable proof that you are the trie owner of the iPad.